Divorced mother Chae-Min-Young (Kim Seo-Hyung) moves into a new studio apartment with her six year old daughter Joo-Hee (Kim You-Jung). Min-Young becomes disturbed when her neighbor, who lives one floor below her, complains about the noise coming from their apartment. Min-Young and Joo-Hee live quietly and do make much noise. Min-Young also notices strange behavior from other neighbors. Min-Young looks to uncover the truth behind the apartment complex.

In the year 1716 a mysterious epidemic stickens men in the country of Japan, dropping the population of men to 1/4th of its prior state. With the drastic reduction of men, the gender roles have become reversed in Japan. Woman become the dominant members of society and males are sought out for the ability to produce childre

Detective Hwang (Sol Kyung-Gu) leads a specialized surveillance team in the police department. Yoon-Joo (Han Hyo-Joo) takes a test to join the team. She's tested on her observation skills and memorization. She passes her test and becomes the newest member of the surveillance team. While, Yoon-Joo takes her test, James (Jung Woo-Sung) and his crime group robs a bank. He stands on the rooftop of a nearby building and directs his team's movements. He doesn't tolerate any mistakes. As soon as Yoon-Joo joins the surveillance team, they are tasked to take down James' criminal group. The surveillance team immediately runs into trouble when they can't identify any of the robbers due to their masks and their efficiency in robbing the bank. Detective Hwang finds one man caught on CCTV near the bank. James gets a new order from a mysterious broker (Kim Byung-Ok) and once again completes a heist. While, the surveillance team goes after James, the mysterious broker also looks to take out James.

Han Sang Eun emigrated to Australia with her family at a young age. Years later, she has completed her law studies in the United States and plans to marry her American boyfriend. Her dad, however, is strongly opposed to their union and has set his heart on her marrying Kim Yeo Joon, the son of his best friend. Sang Eun finds herself exiled to Korea, where she reluctantly teams up with the equally uninterested Yeo Joon to devise a plan that will allow them to avoid their impending marriage.

Korea, the last divided nation on earth, is constantly under political and military tension with the surrounding countries especially with the North Korean nuclear issue. To avoid the second Korean War, the secret service agency NSS exists for the national security on the Korean peninsula. NSS special agents are trained specialists who would use any means to fulfill their mission. They officially do not exist and are not acknowledged or protected by the government. Although they are trained to be cold-blooded killers, there is one taboo they cannot avoid; that is love. Hyeon-jun (Lee Byung-Hun) and Sa-woo (Jeong Jun-Ho) are close friends and rivals in the 707 special forces. They are both recruited into NSS and quickly become the best of the best. Each with different secret assignments, they soon have to take on different paths of life, and even against each other. In a world of conspiracy and betrayal, they both fall for Seung-hee (Kim Tae-Hee), the beautiful but lethal profiling specialist at NSS. They are forced to make their final decision when they are faced against each other in a nuclear terrorist attack, and Seunghee’s formidable secret is revealed.

During a high school music exam to assess the singing abilities of students, Songju shows off his rapping skills despite the blackboard in the background stating that pop and rap songs are not allowed. The teacher gives him an F on the test without saying anything. In the meantime, on one side of the classroom, Juyeon looks happy, watching Songju rap. He loves hip-hop as much as Songju does although these two come from completely different backgrounds. Songju is a troubled student living in a multi-house home in a less developed area while Juyeon is an exemplary student living in a fancy apartment in a rich village. Despite differences in grade, personality, and background, they decide to form a hip-hop duo called LIMECRIME.

There is a rumor of a website called "Hell Correspondence" which only opens at twelve midnight sharp. When a user types the name of a person to be gotten rid of, a hell girl Ai Enma brings the person to the hell. In return, the user will be sent down to hell at the end of his or her life. A high school girl Miho is worried about her friend Haruka being trapped in the evil scheme of a popular rock band after Haruka joins the audition and starts acting strange. As Miho tries to help her friend, she finds herself in the cursed world behind the "Hell Correspondence".

One day sergeant Yip takes a strange statement from a man who was caught peeping at ladies' room. The suspect claims some women plan to kill all men, and he was spying on them to collect the evidence. Later the statement disappears mysteriously, and when Yip tries to take another one, the suspect tells him altogether different thing. Yip gets intrigued and tries to sort this case out.